1. Field of the Invention
The invention relates to a motor vehicle locking device with a lock mechanism with a connection coupling, a lock actuation unit located separately from the motor vehicle lock and having a connection coupling, and with a shaft as a coupling between the connection coupling of the motor vehicle lock and the connection coupling of the lock actuation unit. A motor vehicle locking device for a hood is especially intended here.
2. Description of the Related Art
The known motor vehicle locking device underlying the invention (French Patent 1 175 848 B) has a motor vehicle lock with a lock mechanism and locking elements and with a connection coupling, preferably in the form of a so-called xe2x80x9cnutxe2x80x9d for connecting a coupling means. The motor vehicle lock is located on the inside of a motor vehicle door or at an angle from the inside sheet and the end sheet of the motor vehicle door. Thus, the motor vehicle lock is located at a considerable distance from the lock actuation unit which is located on the outside door wall, generally there in the door handle arrangement, with generally a locking cylinder. The lock actuation unit likewise has a connection coupling for a coupling means. To allow a non-coaxial arrangement of the connection couplings, the coupling means which ensures the transfer of torque from the lock actuation unit to the motor vehicle lock is a flexible shaft here, which is connected to the two connection couplings.
The use of a universal shaft between the connection couplings of a lock actuation unit and of the motor vehicle lock with the same problem is known (European Patent EP 0 722 028 B1).
By actuating the lock actuation unit, under the action of the coupling means, the motor vehicle lock is moved from its locked into its unlocked position. In the unlocked position of the motor vehicle lock, the motor vehicle door can be opened. It has been shown that the coupling means between the lock actuation unit and the motor vehicle lock is a favorite point of attack for attempted theft. Through a hole drilled or forced into the outside door wall, the coupling means can be directly attacked with a tool and it can be turned by force around its lengthwise axis with acceptance of the breaking-off of the coupling means on the connection coupling of the lock actuation unit. The connection coupling on the motor vehicle lock is then subjected to force such that the motor vehicle lock is moved into the unlocked position. The motor vehicle door can thus be opened.
The aforementioned problem is not otherwise limited to the coupling means which ensures torque transfer, even with a non-coaxial arrangement of the connection couplings, but can also occur for a coupling means made simply as a straight, stiff transmission part.
One special problem exists in hood locks, since in modern motor vehicles, under the hood the complete security electronics is housed which must be protected against manipulations and unwanted accesses.
A primary object of the present invention is to provide a known type of motor vehicle locking device with a coupling means between the connection couplings which will provide improved anti-theft protection.
The aforementioned object is achieved by the shaft having an outside jacket which passes essentially completely between the connection couplings, wherein the outside jacket of the connection coupling of the motor vehicle lock cannot be turned in the normal state, wherein the outside jacket is coupled to a blocking element, and wherein, when the outside jacket is forcibly turned around its lengthwise axis, the blocking element blocks the force transmission element of the connection coupling, which element is connected to the shaft or mounted on it, before actuation of the lock mechanism of the motor vehicle lock by the shaft can take place.
Alternatively, the object can be achieved, in a subordinate approach, by the shaft having an outside jacket which passes essentially completely between the connection couplings, wherein the outside jacket cannot be turned in the connection coupling of the motor vehicle lock in a normal state, wherein the outside jacket is coupled to a blocking element, and wherein, when the outside jacket is forcibly turned around its lengthwise axis, a force transmission element of the connection coupling of the motor vehicle lock, which element is coupled to the shaft or made on it, is de-coupled by means of the blocking element from the shaft and/or the lock mechanism of the motor vehicle lock, before actuation of the lock mechanism of the motor vehicle lock by the shaft can take place.
Basically, it is first provided that, for purposes of improved anti-theft protection, the shaft is surrounded with an outside jacket which passes or is completely closed essentially between the connection couplings. Therefore, an encapsulated shaft is used. However, it has been found in tests that reliable anti-theft protection is still not ensured. If the outside jacket of this encapsulated shaft is attacked sufficiently vigorously and at a sufficient distance from the connection coupling on the motor vehicle lock, nevertheless the outside jacket together with the shaft located therein can be turned around the lengthwise axis in order to turn the shaft itself around the lengthwise axis, and thus, to move the motor vehicle lock, in turn, into the unlocked position. As a result, the invention proposes that the outside jacket, when turned forcibly around its lengthwise axis, be used as a switching element for blocking or, in the subordinate approach, for de-coupling of the force transmission element of the motor vehicle lock.
Therefore, in accordance with the invention, reliable actuation of the motor vehicle lock from the lock actuation unit will cause only rotation of the shaft with the outside jacket stationary, while actuation due to a theft attempt leads to rotation of the outside jacket with the shaft, and thus, makes the motor vehicle lock impossible to unlock.
The invention is explained in detail below using the accompanying drawings which show one embodiment in accordance with the invention.